<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
        body {
            background-color: #999;
        }
        
        .container {
            height: 400px;
            width: 600px;
            margin: 20px;
            border: 1px solid #000;
            box-sizing: border-box;
            display: flex;
            justify-content: space-around;
        }
        
        .slider {
            height: 100%;
            padding: 30px 0;
            box-sizing: border-box;
            display: flex;
            flex-direction: column;
            background-color: #ccc;
        }
        
        .slider-container {
            flex: 1;
            margin: 0 20px;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        
        .slider-upper {
            flex-shrink: 0;
            height: 50%;
        }
        
        .slider-upper-line {
            height: 100%;
            margin: 0 12px;
            width: 2px;
            background-color: #e9e9e9;
        }
        
        .slider-middle {
            flex-shrink: 1;
            height: 0;
            width: 0;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .slider-lower {
            flex: 1;
        }
        
        .slider-lower-line {
            height: 100%;
            margin: 0 12px;
            width: 2px;
            background-color: #e9e9e9;
        }
        
        .slider-block {
            flex-shrink: 0;
            background-color: #ffffff;
            width: 20px;
            height: 20px;
            box-shadow: 0 0 2px 2px rgba(0, 0, 0, 0.2);
            border-radius: 50%;
            position: relative;
            z-index: 1;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="slider">
            <div class="slider-container">
                <view class="slider-upper">
                    <div class="slider-upper-line"></div>
                </view>
                <view class="slider-middle">
                    <view class="slider-block"></view>
                </view>
                <view class="slider-lower">
                    <div class="slider-lower-line"></div>
                </view>
            </div>
        </div>
    </div>
</body>

</html>